The present invention relates to an apparatus configured to manufacture tubes, and more particularly relates to an apparatus that includes a rollformer and additional forming devices coordinated with the rollformer to facilitate the manufacture of tube sections with stops and stop-receiving guide channels, and also to facilitate the separation of the tube sections at an end of the rollformer.
There exists a prior art car jack (for lifting a vehicle to change tires) that uses, as part of its assembly for vertical strength, three telescoping tube sections that telescopingly mate together. The three tube sections are configured to longitudinally slide between a collapsed position where all three tube sections lie within each other, and an extended position where all three tube sections extend from each other (with only an inch or so of each tube section overlapping with the next tube section). The arrangement also permits the three tube sections to telescopingly slide together during assembly of the jack. The inner one of the three tube sections includes a first xe2x80x9coutxe2x80x9d dimple. The intermediate one of the three tube sections includes a first channel for receiving the first xe2x80x9coutxe2x80x9d dimple and also includes a second xe2x80x9coutxe2x80x9d dimple. The outer one of the three tube sections includes a second channel for receiving the second xe2x80x9coutxe2x80x9d dimple, and a third channel for receiving the first channel. A first xe2x80x9cinxe2x80x9d dimple is formed at an end of the first channel and is configured to abut the first xe2x80x9coutxe2x80x9d dimple to limit telescoping movement of the inner and intermediate tube sections. A second xe2x80x9cinxe2x80x9d dimple is formed at an end of the second channel and is configured to abut the second xe2x80x9coutxe2x80x9d dimple to limit telescoping movement of the intermediate and outer tube sections.
The above-described three tube sections are made by tube-forming techniques, where a tube section is initially cut to length and then stamped/re-formed to include the various xe2x80x9cinxe2x80x9d dimples, xe2x80x9coutxe2x80x9d dimples, and channels or keyways. However, the tube-forming technique is relatively costly for many reasons. It requires considerable multiple forming steps which result in considerable handling, tooling, and machinery. This in turn results in high labor and processing costs, high overhead, and high in-process inventory, all of which are expensive. Further, there can be considerable variation in the manufactured tube sections, particularly over time as dies wear, which can be problematic because the jack requires that the tube sections maintain tight tolerances that permit smooth telescoping movement without sloppiness or binding. For example, if one tube section has a diameter that is non-round or oversized, the mating tube section will either bind and not telescope, or it will be sloppy and unable to maintain a linear telescoping action such that it will buckle. Also, for example, if a dimple or channel is not properly formed, the dimples will not properly engage to limit telescoping movement, which will result in the jack potentially coming apart, resulting in an upset vehicle owner and/or potential safety hazard.
An apparatus and method of manufacturing tube sections is desired that solves the aforementioned disadvantages and that offers the aforementioned advantages, where the apparatus and method are capable of providing tube sections shaped for telescoping mating use, and are capable of producing the same at high volume, low labor, low cost, and with high dimensional accuracy.
In one aspect of the present invention, an apparatus includes a scoring device for making transverse score lines on a roll of sheet material, and a rollformer adapted to continuously form the sheet material into a tubular shape. A welder is positioned in line with the rollformer and is adapted to weld the tubular shape into a permanent tube. A break-off device positioned in line with the rollformer is adapted to break off sections of the tube at the score lines.
In another aspect of the present invention, an apparatus includes a scoring device for making transverse score lines on a roll of sheet material, the score lines having a non-uniform depth across a width of the sheet material. A rollformer is provided that is adapted to continuously form the sheet material into a tubular shape. A welder is positioned in line with the rollformer and is adapted to weld the tubular shape into a permanent tube.
In another aspect of the present invention, an apparatus includes a scoring device for making transverse score lines on a roll of sheet material, and a dimpler adapted to form a stop dimple at a location coordinated with the score lines. A rollformer is adapted to continuously form the sheet material into a tubular shape having a longitudinal guide channel therein, with the stop dimple being along the guide channel. A break off device is positioned in line with the rollformer is adapted to break off sections of the tube at the score lines.
In another aspect of the present invention, an apparatus includes a roll of sheet metal of at least about 0.075 inches thickness, and a scoring device for making transverse score lines on the sheet metal. A rollformer is adapted to roll the sheet metal into tubular shape. A break-off device is positioned in line with the rollformer that is adapted to break off sections of the tubular shape at the score lines.
In another aspect of the present invention, a method includes steps of providing a roll of sheet material, making transverse score lines in the sheet material, providing a rollformer, and rollforming a tubular shape from the sheet of material using the rollformer. The method further includes welding the tubular shape into a permanent tube, and breaking off sections of the tube in line with an end of the rollformer during the step of rollforming.
In another aspect of the present invention, a method comprising steps of providing a roll of sheet material, making transverse score lines in the sheet material, providing a rollformer, and rollforming a tubular shape from the sheet of material using the rollformer. The method further includes forming a longitudinally extending channel and forming dimples in line with the rollformer in the tubular shape.
These and other aspects, features, and objects of the present invention will be further understood by reference to the following specification, claims, and appended drawings.